The invention relates to an internal combustion engine having a compressor in the induction system with swirl vanes disposed in the inlet passage to the turbine and to a method for operating an internal combustion engine.
DE 199 55 508 C1 discloses a turbocharged internal combustion engine having an exhaust gas turbocharger which comprises an exhaust gas turbine disposed in the exhaust gas system and a compressor disposed in the induction system of the internal combustion engine. The turbine wheel of the exhaust gas turbine is driven by pressurized exhaust gases and the turbine wheel rotation is transmitted by means of a shaft to the compressor wheel which compresses combustion air supplied to the compressor from the ambient air to an increased boost pressure. The compressor wheel is rotatably mounted in a compressor intake duct, by means of which the combustion air is supplied to the inlet end of the compressor. In the compressor, an auxiliary duct is formed parallel to the compressor intake duct, which auxiliary duct opens radially into the compressor intake duct adjacent the compressor wheel. By way of the auxiliary duct additional combustion air may be supplied radially to the compressor wheel blades under certain operating conditions. An adjustable swirl vane structure is arranged in the region in which the auxiliary duct opens into the compressor intake duct, which swirl vane structure provides a propulsive swirl of additional air to the compressor wheel. The air quantity to be supplied may be set by means of a throttle valve in the. axial compressor intake duct.
With the aid of this device, a so-called cold air turbine operation of the compressor may be implemented in which a vacuum prevails in the induction system downstream of the compressor at low loads and speeds of the internal combustion engine, which vacuum causes a pressure drop across the compressor wheel that can be utilized to drive the compressor wheel. In this operating situation, the combustion air is supplied by means of the auxiliary duct which opens radially, into the compressor and causes a swirl providing for an improved drive action on the compressor wheel.
Based on this prior art, it is the object of the invention to provide an internal combustion engine with a compressor in the combustion air intake system so as to reduce the emissions of the internal combustion engine using simple measures.